One type of orthodontic appliance that is known is a custom made retainer or plate appliance that is moulded from bite impressions of a particular patient. The bite impressions are used to make laboratory models of a particular patient's arches and associated dental structures which are then used to mould a customised retainer appliance for fitting that particular patient. A limitation of the retainer appliances is that the cost of producing them is high because they are individually made for each patient.
Orthodontic systems using fixed appliances that are commonly called orthodontic braces are also used for orthodontic treatment. Orthodontic braces comprise a plurality of brackets or bands each of which is mounted over an individual tooth and bonded thereto so that it is permanently mounted on the tooth. The brackets are linked together by means of a wire that passes through wire apertures formed in each of the brackets. The wire applies a force to the brackets that can then be used to reposition and align the teeth on the dental arch. In particular these fixed appliances can be used to bring the anterior teeth on the upper and lower arches in the correct relative position to each other. The wire can progressively be drawn in to retract the incisor teeth on the anterior region of the upper dental arch to “close” an “open” bite. The fixed appliances can achieve some degree of arch expansion together with alignment of the teeth but the extent of the expansion is limited. The fixed appliances use brackets to move teeth on a dental arch, and in particular to align the teeth. For example these fixed appliances can be used to retract protruding teeth, in particular protruding incisors on the upper arch of a user, and they can also be used to advance retruded teeth.
The fixed braces described above have their drawbacks. Firstly Applicant's experience is that most orthodontic patients would choose not to wear braces if an alternative treatment was available. The brackets of the braces are generally unsightly and detract from the patient's looks while the braces are being worn, e.g. for the duration of the treatment. Secondly the braces can be uncomfortable to wear and can cause trauma, such as cuts and bruises to the intraoral soft tissues of a user. The soft buccal mucosa is particularly susceptible to injury from projections on the buccal surface of the brackets. Thirdly the brackets and wire are fixed on the teeth of a patient by an orthodontist and they cannot be removed by the patient. Fourth another shortcoming that has plagued the use of braces is patient relapse where the teeth move back towards their original positions once the brackets are removed. The braces are non-removable appliances that cannot be used on an intermittent basis like a removable plate retainer. The appliance is an active appliance that ceases to have any influence once it is removed.
Aside from the traditional orthodontic treatments described above, in more recent times some treatments have focused on encouraging and promoting improved oral habits as a way of developing an intra-oral environment that is less likely to develop severe class 2 and class 3 malocclusions. The applicant has developed an arch shaped appliance that can train a patient to position certain key intraoral structures such as the tongue in the correct position and to resist the development of malocclusions caused by poor oral habits. One such feature is a tongue tab that assists in positioning the tongue at the correct height and reduces tongue thrusting.
It would be advantageous if a removable orthodontic appliance could be devised that at least ameliorated one or more of the shortcomings of the appliances and treatments described above.